Although adiaphora are free before God because He has neither commanded nor forbidden them, it is sometimes necessary to argue about adiaphora among men; else there would be no Article X of the Formula of Concord. St. Paul does the same thing when he contends against those who were insisting upon circumcision.
It is a shame, though, when such arguments about adiaphora become necessary, because the necessity of the argument robs the adiaphora of their freedom.
To be sure, the freedom of faith never is the freedom of wild anarchy. The Christian does not use his freedom in the Gospel to live selfishly, but unto righteousness in Christ. True freedom therefore orders itself in love, and love is always freely given and freely received. This freedom of faith and love is a freedom for what is good and right and true; it is never a freedom for wickedness. Above all, love will freely contend for the truth of the Gospel, because all true freedom stands or falls with the Gospel. Call it tough love, maybe, but that it why it is sometimes necessary to argue about adiaphora; and that is why adiaphora are not always free.
That is the point to Article X of the Formula of Concord. When adiaphora are pressed upon the church or demanded, as though comprising the worship of God, or as though righteousness were obtained by such works of man, then faith confesses, "Not so!" "I shall not be bound by this law, nor by any other righteousness than Christ." Indeed, faith is bound in such a case to resist and refuse the pressure and demand, precisely because faith clings to Christ and the freedom of His Gospel. So, too, for the same reason, faith resists and refuses to be robbed of adiaphora under any pretense of necessity. What God has neither commanded nor forbidden is free — except where man commands or forbids it in the name of God, on the pretense of divine righeousness; then faith clings alone to God's "Yes" in Christ, and speaks a resounding "no" to man.
Regrettably, we are too eagerly drawn with our sinful egos into such heroics. We itch for the confrontation, when we can rebuke Peter to his face or stand with Luther at the Diet of Worms. We are more prone to seek the glory of martyrdom than the quiet sacrifice of love for the neighbor. It is easier and more fun to fight than to concede the point before it becomes an argument of necessity. That is the error of those who push too hard and too fast with something that is otherwise free and good, and it is no less the error of those who react too quickly and too harshly against that which really is free. It does not matter, to this extent, whether one's hobby-horse is "traditional" or "contemporary." There are villains and victims on both sides.
In fact, when arguments over adiaphora are engaged unnecessarily, then everyone loses. Then freedom is forfeited and the Gospel is obfuscated. Then both faith and love are victimized. That is not free but sinful, and these are the greatest tragedies of all. But there is also the collateral damage of God's good gifts, which are freely given to be freely received with thanksgiving, and to be sanctified by the Word of God and prayer, but which are trodden under foot in the midst of combat. Such losses ought to sadden Christians on all sides. Such losses delight the demons.
Arguments about adiaphora are necessitated by attacks on the Gospel, and they ought not to be agitated by anything less or anything else.
Nevertheless, it should be understood that arguments are sometimes necessary. Some battles have already begun before we have arrived. Some things are not truly free to our use, even if they may be called "adiaphora," because they undermine or contradict the Word of God. Even though all things are free before God in faith, because there is no condemnation for those who are in Christ Jesus, not all things are meet, right and salutary. Not all things serve faith and love by serving and supporting the clear and consistent catechesis and confession of the Word of God. Faith will recognize when it is the Gospel that is at stake, and it will stand accordingly; and love will know when it must be tough and when it must sacrifice self for the sake of the neighbor.
It is neither safe nor right to act against one's conscience. Let us understand, however, that where it is a matter of conscience, then faith and love are more ready and willing to die than to kill. But faith and love will also contend, even argue and fight, for the sake of the neighbor. It is not so hard to know what is necessary when faith is fixed on Christ and love is focused on the neighbor.